Security concerns with used and rooted M9?

Hi,
My provider gave me the option to buy a slightly used M9 that a customer had returned in the first few days of their contract apparently. I liked the idea of saving money so I bought it. I have found though that the previous owner had rooted the phone and at least added TWRP recovery to it and SuperSU. From everything I can tell the phone is still running an official HTC rom . My question is whether there is any chance the previous owner left something nasty behind. Any advice about how to check for this or am I just too paranoid? Assuming I can get a stock HTC rom is the a process by which I can completely wipe all memory in the phone and fully restore it to stock, or at least to a point where I'm confident that everything on it is from me and only me?

Thanks

Just received my Fire Phone (Ebay) and battery was completely discharged... concerns?

Hello all... I've just received the FIre Phone I ordered off Ebay (qualitycellz seller). The phone is supposedly brand-new in original box, but upon taking it out of the box and trying to turn it on it did not respond at all. I connected the charger, tried again, nothing...... had to leave it connected for around 5 minutes and tried again and this time the screen woke up to show me the ultra low battery indicator with a 0% charge level. I had to wait for it to charge for around 5 minutes to re-attempt turning it on. Fortunately it did turn on after that time.

My concern is that from what I know all cellphone manufacturers ship phones with at least 60% charge in order to keep the battery in good condition while on storage, so receiving the phone completely dead raises a concern on me that there might be damage to the battery. Could this be related to the long time Amazon had these units in storage since the phone launched?... I would expect that these phone might have been around a year in storage before Amazon decided to pull the plug.

This is the seller that Amazon unloaded all their remaining Fire Phone inventory to, so phones are new in box. I'm also concerned that the seal on the box was broken, even though the phone and packaging inside did not show signs of being used in any way. The phones are AT&T version but they include an unlocking code, so they should not need to open the box in any way since they generate the Unlock code based on the IMEI visible on the box label. One option is that they open the boxes to confirm that the phones are not DOA and then they forgot to turn it off after testing.

Should I be concerned about this?... I've not activated the phone yet and I've contacted the seller first to at least request their explanation and thoughts on this, and check if we should proceed with a return on this case. Your comments are appreciated.

Battery health concerns

I just bought a second hand Lg G Watch R on an Ebay, I suspect from the strap wear and tear pictures that it had been taken by at least two people.

I am afraid now they didn't took care of it and leaved it without charge, and the battery could be damaged.
Is there a test so I can check the watch battery health once I receive it ? Like a screen on time timer ?

Concerns about the new Leather style

I skipped the 2014 Moto X, planning on upgrading this year to the 2015 Moto X Pure. I've been looking forward to purchasing a leather back option, but I'm just noticing this year's version has different leather. It's textured "saffiano leather" from what I've seen on Android Police and other sites. I'm concerned this leather looks fake and plastic-y. I'd love to hear what other XDA users think, still decent looking leather, soft and not face looking? Thanks!